Various types of ink jet nozzle assemblies are known where a displaceable element arranged in a nozzle chamber effects ink ejection through a nozzle opening of the nozzle assembly. In certain of these devices, the moveable element is, itself, an actuator. In other devices, an actuator is arranged externally of the nozzle chamber and is connected via an opening in a wall of the nozzle chamber to the displaceable element. Where the actuator is arranged externally of the displaceable element, a seal needs to be provided to minimise ink loss through such opening.
In yet other embodiments, the nozzle itself is displaceable for effecting ink ejection. In this case, ink loss around a periphery of the nozzle needs to be minimized.